English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

High-Pressure, High-Temperature Single-Crystal Growth, Ab initio Electronic Structure Calculations, and Equation of State of ε-Fe3N1+x

MPS-Authors
/persons/resource/persons126783

Niewa,  R.
Max Planck Institute for Chemical Physics of Solids, Max Planck Society;

/persons/resource/persons126912

Wosylus,  A.
Max Planck Institute for Chemical Physics of Solids, Max Planck Society;

/persons/resource/persons126750

Meier,  K.
Chemical Metal Science, Max Planck Institute for Chemical Physics of Solids, Max Planck Society;

/persons/resource/persons126644

Hanfland,  M.
Max Planck Institute for Chemical Physics of Solids, Max Planck Society;

/persons/resource/persons126841

Schwarz,  U.
Ulrich Schwarz, Chemical Metal Science, Max Planck Institute for Chemical Physics of Solids, Max Planck Society;

External Resource
No external resources are shared
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Niewa, R., Rau, D., Wosylus, A., Meier, K., Hanfland, M., Wessel, M., et al. (2009). High-Pressure, High-Temperature Single-Crystal Growth, Ab initio Electronic Structure Calculations, and Equation of State of ε-Fe3N1+x. Chemistry of Materials, 21, 392-398. doi:10.1021/cm802721k.


Cite as: http://hdl.handle.net/11858/00-001M-0000-0015-25A2-8
Abstract
The high-pressure behavior of the hard material epsilon-Fe3N1+x was studied up to 33 GPa with in situ X-ray diffraction experiments using diamond anvil cells in combination with synchrotron radiation as well as by ex situ high-temperature, high-pressure treatment at 1600(200) K in a two-stage multianvil device with a Walker-type module. Evaluation of the pressure-volume data up to 10 GPa by fitting a Murnaghan-type equation reveals a bulk modulus of B-0 = 172(4) GPa (B' = 5.7, fixed). The calculated bulk modulus (220 GPa) on the basis of density-functional theory (GGA-PAW-PBE) is in satisfying agreement with the experimental one. Single crystals of epsilon-Fe3N1+x as obtained by ex situ high-temperature, high-pressure experiments reveal in X-ray diffraction data refinements a structural model of iron atoms in the motif of a hexagonal close packing with occupation of octahedral voids by nitrogen atoms exhibiting long-range order. The preferred structural model is described in space group P312 (a = 4.7241(2) angstrom, c = 4.3862(2) angstrom, V = 84.773(6) angstrom(3), Z = 2, R(F) = 0.0339, wR(F-2) = 0.0556) and compared to a second model in P6(3)22. This choice of structural description is corroborated by the results of density-functional calculations. These yield a total energy at 0 K, which is 5 kJ/mol lower for the model in space group P312 compared to the second best alternative arrangement. Using micro- and nanoindentation techniques, a Vickers hardness of H-V = 7.4(10) GPa, a nanoindentation hardness of H = 10.1 (8) GPa, as well as a reduced elastic modulus in the amount of E-r = 178(11) GPa were measured for epsilon-Fe3N1+x single crystals.